So I have ALL stuff in install options unchecked, I have no any marketplace plugins installed. Installation window says that engine takes 17.88GB of space, but it’s not. My fresh installed UE 27.2 Engine folder takes up almost 90GB of disk space.
I have “Templates and Feature packs” unchecked, but Templates folder takes up 2.44GB, I have all of target platforms unckecked but Binaries folder has a bunch of platform folders and only that folder took 29GB of space. Also every plugin folder has that binaries also, so plugins folder takes up another 33.5GB of space.
I have “Engine Source” unchecked but Source folder takes up 8.3GB. And every plugin has Source files also.
Is it supposed to work this way?
I’ve installed this version before and as I remember it took only about 20GB of space.
Nice, I just marked random checkbox and it cleaned all that folders. 
So by default it downloads all the stuff even if before you installed only engine core.